let arr1 = [1,2,3,4];
let arr2 = [...arr1];
let arr3 = [..."hello"];
let obj1 = {
  name: "张三",
  age:12
}
let obj2 = {
  // name:obj1.name,
  // age: obj1.age,
  ...obj1,
  gender: '男'
}
console.log(obj2);